They're foreign. They must be idiots
My first question would be what, exactly, the Chinese are supposed to be stealing. Knowledge of how to build high speed trains? China has 27000km of HSR trackage. The US has a few hundred km. Same story in many other fields. With a few exceptions -- fighter jet engines, cutting edge semiconductors -- Chinese technology genuinely seems reasonably competitive with the West. If not better.
My feeling -- The folks pushing this story are the 21st century equivalent of the mid 20th Century experts who claimed that Japanese technology was entirely derivative and besides which Japanese had genetically weak eyes that would be ineffective in aerial combat. Turned out that the Mitsubishi A6M ("Zero") was a better fighter than its American/British counterparts and that the Japanese pilots had no trouble at all targeting American, British, and Dutch ships in late 1941.